Acid-Base Physio

Question 1

Maintenance of proper pH? (3)

Answer 1

1. Intr/extracellular buffer of body fluid
2. Respiratory mechanics (CO2)
3. Renal mech (excrete H+-reabsorb & produce HCO3-)

Question 2

normal pH of blood

Answer 2

7.4

Question 3

acid classifications in humans; exist as one of two forms:

Answer 3

volitle acids: can be breathed out (CO2)
Fixed acids: produced by metabolism 
      sulfuric (protein metabolism)
      lactic
      ingested acids

Question 4

acids assumed to dissociate completely when in aqueous solution

Answer 4

strong

Question 5

acids dissociate only slightly in aqueous solution–majority of molecules remain undissociated

Answer 5

weak acid/ conjugate bases

Question 6

chemicals and proteins that can absorb free H+ or donate a H+, so pH change only minimally

Answer 6

buffer

Question 7

buffer capacity is critical– otherwise we would see…

Answer 7

wild changes in tissue pH (locally and systemically w/ normal activities)

Question 8

pH =

Answer 8

H+ concentration

pH = -log[H+}

Question 9

point at which, for given acid or base, equilibrium is reached btwn the dissociated form ({H+} & {A-}) and the associated form ({HA})

Answer 9

K – Equilibrium Constant

Question 10

K=

Answer 10

[HA]

Question 11

K for HCL will be

Answer 11

a huge number

Question 12

pK for acid is midpoint btwn

Answer 12

HA and A-

Question 13

At equal concentrations [A] and [HA], pH =

Answer 13

pK

Question 14

curve plotted for pH of solution w/ buffer, while adding acid or base will be ________ in shape

Answer 14

sigmoidal–additions will look flat at high and low end

slide 7

Question 15

3 main buffers in extra cellular fluid ECF

Answer 15

1. bicarbonate HCO3-
2. inorganic phosphate
3. plasma proteins (trade Ca++ for H+)

Question 16

HCO3- (pK, normal conc.?)

Answer 16

Most important buffer in humans
pK=6.1
18-28 mEq/L

Question 17

albumin has ____ charge so neutralized when add ____

Answer 17

negative,

H+

Question 18

inorganic phosphate pK

Answer 18

6.8

Question 19

*in blood: H+ + HCO3- –> <–

imp equation for other things

Answer 19

H2CO3 –>Ca++ takes spots on albumin–> hypocalcemia (low free calcium in blood) –> CARPAL PEDAL SPASM

Question 20

2 ICF buffers

Answer 20

1. organic phosphates

2. proteins (HEMOGLOBIN, deoxyhemoglobin)

Question 21

treatment for Carpal Pedal Spasm

Answer 21

rebreath CO2 out of paper bag

Question 22

Renal mechanisms in acid-base balance (buffer)

Answer 22

1. reabsorption of filtered HCO3-

2. synthesize HCO3- ( for each H+ excreted, 1 HCO3- made)

Question 23

kidneys excrete________, maintaining acid-base balance

Answer 23

1. fixed acids

2. H+ as NH4+

Question 24

pulmonary balance of acid/base is _________, maintains pH by varying _______ ________, which changes ______ and therefore pH

Answer 24

rapid,
minute ventilation,
PCO2

Question 25

blood pH of less than 7.35 (^ in H+ or v in HCO3-)

Answer 25

acidemia/ acidosis

Question 26

watch video on CO2 HCO3- H+ H2O relationship

Answer 26

renal mechanics of acid-base

Question 27

disorder of pH greater than 7.45 from decreased H+ concentration

Answer 27

alkalemia/ alkalosis–secondary to ^ minute ventilation

Question 28

Acidemic or Alkalemic disorders subdivided into: (2)

Answer 28

1. Metabolic acid-base disturbances

2. Respiratory acid-base disturbances

Question 29

Metabolic acid-base disturbances usually from

Answer 29

increased fixed acids, sometimes decrease in HCO3-

1. ^ non-vol acid production
2. decrease renal acid excretion
3. dec renal HCO3- synthesis
4. loss of alkali (HCO3-)

Question 30

Respiratory acid-base disturbances from

Answer 30

disturbance in PCO2 from (respiratory acidosis vs. alkalosis)

Question 31

fixed acids aka

Answer 31

nonvolatile acids

Question 32

pH identifies disorder as acidemic or alkalemic,
PCO2 levels ID a ______ component to pathophys
HCO3- levels ID a _______ component to pathophys

Answer 32

respiratory,

metabolic

Question 33

for each change in PCO2 of 10mm, pH will change by appx. ____ in _________ direction

Answer 33

0.08, appx 0.1

OPPOSITE

Question 34

2 primary mechanisms used to maintain pH

Answer 34

1. respiratory compensation–rapid PCO2 change(^ minute ventilation to exhale CO2)
2. renal compensation–HCO3- and acid excretion

Question 35

• pH 7.5 dx

will be one of these on exam–examples in ppt

Answer 35

low PCO2 or

high HCO3

Question 36

*pH 7.28 dx

Answer 36

low HCO3- (bicarb) or

high PCO2

Question 37

respiratory acidosis from

Answer 37

hypoventilation (3)

 1. CNS problems (drugs, TBI, tumor, stroke)
 2. Pulmonary disease states (COPD, asthma, pneumothor)
 3. Neuromuscular disease (tetanus, botu, poison)

Question 38

aspirin

Answer 38

salacilic acid–lower pH

Question 39

respiratory alkalosis from

Answer 39

hyperventilition (6)

1. anxiety
2. hypoxia
3. pregnancy (^ estrogen)
4. High altitude (relative hypoxia)
5. sepsis
6. physiological response to metabolic acidosis          ("metabolic acidosis w/ a respiratory compensation")

Question 40

metabolic acidosis from (3)

Answer 40

1. over-production of acid
   a. diabetic keto-acidosis
   b. lactic acidosis
2. decreased excretion of H+ (RENAL FAILURE)
3. loss of HCO3- (GI or renal losses)

Question 41

a measure of unmeasured anions (-)

Answer 41

anion gap

Question 42

anion gap used to

Answer 42

refine the ddx of METABOLIC ACIDOSIS

Question 43

measure of cation concentration vs. anion concentration

Answer 43

anion gap test

Question 44

normal anion gap range

Answer 44

8-16

Question 45

If bicarb is lost, body hold onto___ to lessen _____ ______

Answer 45

chloride,

anion gap

Question 46

anion gap can be used to confirm _______ ________ or loss of _______

Answer 46

metabolic acidosis,

HCO3-

Question 47

way of differentiating types of metabolic acidosis

Answer 47

anion gap ( i.e. too much acid vs. not enough bicarbinate)
confirmatory of clinical findings (i.e. does pt have diarrhea?)

Question 48

low anion gap indicative of

Answer 48

hypoalbuminemia

Question 49

normal anion gap w/ acidosis indicative of

Answer 49

pt loss of HCO3-

Question 50

if anion gap is increased indicative of

Answer 50

pt has “extra acid” in system

Question 51

acid =

Answer 51

cation